A honeycomb structure has a structure which is created through the following process. A plurality of porous honeycomb segments made of silicon carbide or the like are bonded with one another by use of bonding layers of an adhesive agent, and thus a honeycomb segment assembly is fabricated. Then, the honeycomb segment assembly is ground, and is worked out, into a shape with a desired outer form such as a rounded cross section. Subsequently, the periphery of the honeycomb segment assembly thus ground is coated with a coating material. This honeycomb structure is used for cleaning exhaust gas by depositing the honeycomb structure in an exhaust system of a diesel engine.
Each of the honeycomb segments includes a large number of channels, which are partitioned from one another by porous partition walls, and which penetrate through the honeycomb segment in a uniaxial direction. In addition, abutting channels are blocked at alternate ends. In other words, a channel is opened at an end, and is blocked at the other end. Another channel abutting on the channel is the other way round.
Once exhaust gas flows into a channel from an opened end of the channel, the structure causes the exhaust gas to pass through the porous partition walls, and to flow out of the abutting channels. While the exhaust gas is passing through the partition walls, particulates in the exhaust gas are captured by the partition walls. Thereby, the exhaust gas can be cleaned.
A conventional method of manufacturing such a honeycomb structure has been as follows. Honeycomb segments are fabricated in a way that the honeycomb segments are, for example, square cross-sectioned. The periphery (side surfaces) of each of the honeycomb segments thus fabricated is coated with an adhesive agent such as a ceramic slurry. Thereafter, the honeycomb segments are placed in arrays on a supporting jig. The honeycomb segments thus placed are pressed against one another in a way that the honeycomb segments are brought into full contact with one another. Subsequently, the honeycomb segments are ground, and are worked out, into a predetermined shape. (Japanese Patent Laid-open Official Gazette No. 2000-7455)
However, in a honeycomb structure manufactured by use of the conventional manufacturing method, cracks may occur in some cases.